Crank case venting system



Sept. 25, 1934. R. CHILTON CRANK CASE VENTI'NG SYSTEM Filed Jan. 14.1932 EV r-i l N VEN TOR 7Bm-.HND C'I//LToN l rlllilllll..

Patented Sept. 25, 1934 N reussi' CR/ANK CASE VENTNG SYSTEM RolandChilton, RidgewoodyN. J., assigner to Wright Aeronautical Corporation,Paterson,

N. J., a corporation of New York Application January i4, 1932, serieuNe. 586,600.

4, Claims. (ci. 1an-194) My invention relates to improved means forventing the housings of lubricated mechanisms and more particularly tocranlrcase venting of in- I, ternal combustion engines. y Much troublehas been experienced with oil leakage through the breathers or vents ofthe cranlrcases of radial aircraft engines due (l) to the extremecompactness of the crankcases (2) n `to the violent air pulsations setup by the pistons and counterweights, and 3) to the relatively largevolume Yof piston leakage which must be provided for. It is the usualpractice in radial aircraft engines to vent the nose end of theYcranlrcase because this particular part of the Vcranlrcase contains theleast amount of agitated oil. Notwithstanding such precaution, breatherleakage is the rule` rather than the exception, especially in gearedengines where additional agiy tation or splashing occurs atthe nose orforward .20 cranlzcase end where the gear train is encased.

in my copending application, Serial No. 539,836, filed May 3l, 1931, asatisfactory form oi crankcase venting arrangement is disclosed. Due tothe 'fact that the vapors escape from the center of *rotation alongtheaxis of the crankshaft, little or no oil leakage can occur. Centrifugalforce within the crankcase tends to effectively separate the vapor andthe oil. Such system, however, has 4Mits disadvantages since, due topropeller interference, itis difficult to connect a pipe to the vent orbreather as is often desired in order to bring the ultimate outlet to apoint where the condensation which occurs will not be objectionable. Theprincipal object, therefore, of the present invention is to provide avent or breather at or near the center of rotation of the crankshaftwhich may be piped up to any convenient point of ultimate outlet, such,for instance, as the carburetor air intake. Other objects and advantagesof the invention will be hereinafter set forth.

Fig. l is a longitudinal section through the nose casing oi a gearedradial engine; and

Figs. 2 and 3 are, respectively, sections through the passages 36 and 34of Fig. l.

in the drawing, wherein there is disclosed (Fig. l) a longitudinalsection through the nose casing oi a geared radial engine, designatesthe crankcase and 12 the nose. The crankshaft 14 59- bi the engine isextended at 16 to form journals for the support of the bearings 18 and2() of the propeller shaft 22, said shaft being located in the nosehousing 12 by the propeller thrust bea-ring 24. This bearing mayconveniently be secured by the flange 26 of the fixed gear 28 of theplanetary gear indicated in general at 3Q. The particular form ofplanetary gear is not a part of the'present invention. it need not bedescribed, therefore, in greater detail except to l point out that thepropeller shaft 22 is provided with a flange 32 which comprises theplanet supporting member, and that at the point of juncture of the shaftand flange there is provided an annular breather opening 34; within theiixed gear 28. The details of the planetary gear system are disclosed ina co-pending application filed concurrently herewith, .Serial llumber586,601.

Outside of the thrust bearing 24 there is formed in the nose housing 12an annular space 36, the Wall of which is preferably inturned at 38around the bearing nut 40, a linger 42 being interposed between the nut40 and Vthe bearing 2s to prevent oil leakage at this point.Communicating with the annulus 35 is the breather passage 44 which maybe piped up to any convenient point, the passage le in the presentembodiment extending radially upward ironi the annulus 36.

It will now be seen that ample area for the escape of crankcase Vapor isprovided by the annular space 34 under the:v fixed gear 28. The hub 27of the fixed gear 28, by its rearward extension from the flange 26attached to the nose casing 12, forms a baflie to limit the ilow of oiland air through the annular space 34. Any Vapor entering here must do soagainst the centrifugal action imparted by the rotating shaft 22 andflange 32, the latter acting as a inger whereby the heavier particleswill be separated from the lighter Vapor which will escape through thebearing 24 as indicated by the arrows. It will be noted that the bearing24 is of the anti-friction type, utilizing an inner bearing race Li5mounted on the propeller shaft 22, and an outer bearing race 47 mountedin the nose casing l2. The balls 49 or equivalent rollers, form thebalance of the bearing 24, and by the interposition of such balls 49between the outer race 47 and the inner race 45, an annular space orpassage is formed therebetween, which space, normally occurring in anyball or roller bearing of similar type, is given a new use in making itpart of the breathing path for the engine.

As an additional precaution against the accumulation of oil in theannulus 36 a drain connection 46 may be employed. Preferably the drainconnection 46 is in communication with the main drain 48 by means ofwhich the used oil from the casing is scavenged.

It is to be understood that the above described embodiment of theinvention is for the purpose of illustration only, and various changesmay be made therein without departing from the spirit and scope of theinvention.

I claim as my invention:

1. In an engine, a casing, a bearing race mounted therein, a shaftprojecting through said bearing race in annularly spaced relationthereto, and an annular bafiie carried by said casing and extendinginwardly from said race in annularly spaced relation to said shaft, theannular space between said shaft and said bafe and outer race,respectively, forming a vent passage for said casing.

2. In an engine, in combination, a casing, a bearing race in saidcasing, a shaft projecting through said bearing race in annularly spacedrelation thereto, a substantially cylindrical gear hub fixed to saidcasing and extending inwardly in annularly spaced relation to saidshaft, a planet gear holding plate projecting outwardly from said shaft,said plate being spaced from the inner end of said gear hub, a gearcarried by said hub engageable with said planet gears, the annular spacebetween said hub and said shaft, and

vrshaft and said gears, and the annular space between said shaft andsaid casing.

4. In combination, a breathing system for an engine including a casing,a shaft borne therein in annularly spaced relationship thereto, and areduction gear mechanism having a gear iixed to said casing andconcentric to said shaft, said gear being annularly spaced from saidshaft, the annular space between said gear and said shaft communicatingwith the annular space between said casing and said shaft to provide abreathing` duct for the engine.

ROLAND CHILTON.

